Oldspeak: “At the peak of the Arctic outbreak, temperatures may be between 20°F and 40°F below average in large parts of the continental U.S., with dangerous wind chills affecting cities like Minneapolis, Chicago, Cleveland, St. Louis, Washington, D.C., New York, and Boston. The U.S. will have the dubious distinction of experiencing the largest cold temperature anomalies of any land area in the Northern Hemisphere during the height of the biting cold… The cause of the Arctic outbreak can be traced to northeastern Canada and Greenland, where an area of high pressure and relatively mild temperatures is set to block the eastward progression of weather systems, like an offensive lineman protecting the quarterback from the other team… The atmospheric blocking is forcing a section of the polar vortex to break off and move south, into the U.S. The polar vortex is an area of cold low pressure that typically circulates around the Arctic during the winter, spreading tentacles of cold southward into Europe, Asia, and North America at times. Except this time, it’s not a small section of the vortex, but what one forecaster, Ryan Maue of WeatherBELL Analytics, called “more like the whole enchilada” –Andrew Freeman

“More than half the US population is under a wind chill warning as a blast of freezing Arctic air sweeps south and east across the country, bringing the coldest temperatures for decades… The US saw colder temperatures than Almaty, Kazakhstan, where it was -22C (8F), Mongolia at -23C (-8F) and Irkutsk, in Siberia, at -33C (-27F)… The National Weather Service has issued life-threatening wind chill warnings for temperatures as low as -51C (-60F) in western and central Dakota and officials in Indiana – hit by high winds and more than a foot (30cm) of snow – urged residents to stay indoors. –Duncan Barkes

“When America is colder than fucking Siberia, something is terribly, terribly wrong. Entire weather patterns are being drastically altered on a regular basis. The temperature dropped 50 degrees in 3 HOURS yesterday in New York. Last year the polar vortex, that’s always supposed to stay in or near the arctic, was cleaved in two and moved south as a result of arctic warming via loss of sea ice. This year, the whole fucking thing moved south in one direction at once. As the climate warms the irreversible feedback loops currently in progress will accelerate. Weather will become less and less predictable and more and more extreme. Meanwhile, at the same time record cold grips North America, record heat is wilting Australia. This is the new normal. The era of stable climate has passed.” -OSJ

Notice how it has those big ‘loopy waves’ (aka high-amplitude Rossby Waves). It is the big swoop southward that is ushering in the current frigid polar air.Arctic Outbreak: When the North Pole Came to Ohio

by Andrew Freedman, climatecentral.org — Jan 2, 2014

[…]
At the peak of the Arctic outbreak, temperatures may be between 20°F and 40°F below average in large parts of the continental U.S., with dangerous wind chills affecting cities like Minneapolis, Chicago, Cleveland, St. Louis, Washington, D.C., New York, and Boston. The U.S. will have the dubious distinction of experiencing the largest cold temperature anomalies of any land area in the Northern Hemisphere during the height of the biting cold.
[…]The cause of the Arctic outbreak can be traced to northeastern Canada and Greenland, where an area of high pressure and relatively mild temperatures is set to block the eastward progression of weather systems, like an offensive lineman protecting the quarterback from the other team.

The atmospheric blocking is forcing a section of the polar vortex to break off and move south, into the U.S. The polar vortex is an area of cold low pressure that typically circulates around the Arctic during the winter, spreading tentacles of cold southward into Europe, Asia, and North America at times. Except this time, it’s not a small section of the vortex, but what one forecaster, Ryan Maue of WeatherBELL Analytics, called “more like the whole enchilada” in a Twitter conversation on Thursday.
[…]

Computer model projection showing the location of the polar vortex (outlined in orange) and areas of below average temperatures (green and blue) and above average temperatures (orange and red), as indicated by the height of atmospheric pressure levels. The annotations show the cold temperature anomaly in the U.S.and mild anomalies across the Arctic. Credit: WeatherBELL Analytics.

The Arctic Vortex is supposed to stay in the Arctic. It is supposed to form a tight circle, racing around the pole. It is not supposed to branch out and send frigid polar air to the temperate mid-latitudes. At least not on a ‘regular basis’.

But then again, unusual stratospheric warming in the Arctic, is not supposed to be breaking that Polar Vortex up into smaller pieces, either.

Just because it’s out of sight, doesn’t mean it should be out of mind.

[Note: most of what follows is analysis of last winter’s arctic events — which are looking remarkably similar to this winter’s arctic events.]

[…]Sudden stratospheric warming events take place in about half of all Northern Hemisphere winters, and they have been occurring with increasing frequency during the past decade, possibly related to the loss of Arctic sea ice due to global warming. Arctic sea ice declined to its smallest extent on record in September 2012.
[…]Sudden stratospheric warming events occur when large atmospheric waves, known as Rossby waves, extend beyond the troposphere where most weather occurs, and into the stratosphere. This vertical transport of energy can set a complex process into motion that leads to the breakdown of the high altitude cold low pressure area that typically spins above the North Pole during the winter, which is known as the polar vortex.

The polar vortex plays a major role in determining how much Arctic air spills southward toward the mid-latitudes. When there is a strong polar vortex, cold air tends to stay bottled up in the Arctic. However, when the vortex weakens or is disrupted, like a spinning top that suddenly starts wobbling, it can cause polar air masses to surge south, while the Arctic experiences milder-than-average temperatures.
[…]

Ok, what’s a Rossby Wave and how does global warming effect them? (If you have a low threshold for watching videos, this is the best one of the bunch, imo.)Jennifer Francis – Understanding the Jetstream (and Rossby Waves)

Published on Jan 18, 2013 — WTHI-TV
Here’s an meteorological map analysis of various Arctic Vortex splits, what causes them, and what they lead to (… record cold in the Mid-Latitudes).Stratospheric Warming by The SI Weather

Sudden Stratospheric Warming Split the Polar Vortex in Two.the polar vortex was intact at 50 millibars(height in m) on January 1 to 3.

the polar vortex had broken in two (50millibar heights in m) on January 10 to 13

Finally, here’s a good old-fashioned science satellite composite (it’s a very short clip), that shows what happens when the Polar Vortex, gets nudged into going for ‘a power walk’.GMAO – GEOS-5 Stratospheric Sudden warming Event

Many locations may see their temperature readings drop to near record values.
[…]

Incredibly, it may feel as cold as -50 to -60 on Sunday night over sections of the north-central states with the frigid air remaining in place into early next week.

As the vortex shifts eastward, the polar air will begin to affect the Great Lakes and Ohio Valley with temperatures plummeting rapidly.

While the air mass will modify, temperatures will remain downright cold with the forecast high in Chicago, IL being only -11 on Monday.

A strong frontal boundary surging eastward ahead of the polar air mass will become rather active as it intercepts increasing amounts of low-level moisture.
[…]

If only those record-melting Arctic ice packs would stay in place and not keep warming up their supposed-to-be Arctic neighborhoods by exposing all that open sea water — then maybe that Arctic Vortex might not have to ‘go wobbling around like a wildly spinning top — losing its fast-track momentum‘ … at such an ever increasing rate.

But then again, Who needs stable Jet Streams anyways?

Certainly not farmers, not foresters, not ranchers; Certainly not suburban folks who hate all these crazy arctic deep freezes … the ones who ask, “Why in the world, is it so damn cold, anyways?”